/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.dolphinscheduler.server.master.dispatch.host;

import org.apache.dolphinscheduler.remote.utils.Host;
import org.apache.dolphinscheduler.server.master.dispatch.context.ExecutionContext;
import org.apache.dolphinscheduler.server.master.dispatch.enums.ExecutorType;
import org.apache.dolphinscheduler.server.master.dispatch.host.assign.HostWorker;
import org.apache.dolphinscheduler.server.master.registry.ServerNodeManager;

import org.apache.commons.collections.CollectionUtils;
import org.springframework.beans.factory.annotation.Autowired;

import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.Set;

/**
 * common host manager
 */
public abstract class CommonHostManager implements HostManager {

  /**
   * server node manager
   */
  @Autowired
  protected ServerNodeManager serverNodeManager;

  /**
   * select host
   *
   * @param context context
   * @return host
   */
  @Override
  public Host select(ExecutionContext context) {
    List<HostWorker> candidates = null;
    String workerGroup = context.getWorkerGroup();
    ExecutorType executorType = context.getExecutorType();
    switch (executorType) {
      case WORKER:
        candidates = getWorkerCandidates(workerGroup);
        break;
      case CLIENT:
        break;
      default:
        throw new IllegalArgumentException("invalid executorType : " + executorType);
    }

    if (CollectionUtils.isEmpty(candidates)) {
      return new Host();
    }
    return select(candidates);
  }

  protected abstract HostWorker select(Collection<HostWorker> nodes);

  protected List<HostWorker> getWorkerCandidates(String workerGroup) {
    List<HostWorker> hostWorkers = new ArrayList<>();
    Set<String> nodes = serverNodeManager.getWorkerGroupNodes(workerGroup);
    if (CollectionUtils.isNotEmpty(nodes)) {
      for (String node : nodes) {
        serverNodeManager.getWorkerNodeInfo(node).ifPresent(
            workerNodeInfo -> hostWorkers
                .add(HostWorker.of(node, workerNodeInfo.getWorkerHostWeight(), workerGroup)));
      }
    }
    return hostWorkers;
  }
}
